OZFURYFAN wrote:
Hi All,looking for info on the stall strip located on the RH wing of the Corsair,have noticed that various restorations have it & some don't.Can anyone tell me the history or how the aircraft behaves with & without,was it only on particular dash no's or all.I am aware of the function of a stall strip but would like to know more in this instance,best regards,Pete
In high powered prop fighters, low airspeed and angle of attack are critical factors if sudden power is applied as in a go around. This has killed a lot of ham handed pilots. The problems are quite complex and affect the aircraft in different axis, sometimes coupling the axis which can cause a loss of control as the sudden power is applied.
The factors in play as this happens are as I said complex. You have slipstream effect, P Factor as the relative wind forms an angle other than 0 with the thrust vector, and gyroscopic precession as the prop arc transits in pitch. These are corrected in YAW .The REAL killer in the sudden power application/high angle of attack scenario however involves torque.
As the power is applied assuming a Corsair, Mustang, or any one of the single prop American fighters (reverse for a Griffon Spit for example) engine torque which is a correction in ROLL not yaw, pulls the left wing down (an aileron correction). What happens is that the down going wing increases the angle of attack as opposed to the right wing taking the aircraft into an asymmetrical stall situation if and when the left wing reaches it's max CL before the right wing. What kills you is that at low airspeed and high angle of attack you have little aileron control to counter the torque. You might have rudder authority due to slipstream effect but all you have going for you with the ailerons is whatever energy the relative wind can give you at your present airspeed which in almost every case might not be enough to counter the torque induced roll moment.
When CLmax is reached in this manner, the stall is extremely violent and left wing down causing an un-commanded roll that on a go around can be and most often is unrecoverable.
Not sure who did the mod on the Corsair, but I believe it was a field mod placing a 6 inch stall strip on the right wing. Its purpose was to allow symmetrical stall by forcing the right wing into it's CLmax with the left when a roll moment was present causing the wings to break evenly.
I will add here as well that even with the stall strip, ramming in a fast ton of manifold pressure at high angles of attack in an F4U or ANY high performance prop fighter for that matter might not be recoverable on a go around.
The stall might break with less roll, but the recovery remains a reduction in angle of attack and lack of room to accomplish this can still be a serious issue in these airplanes.
Hope this helps a bit.
Dudley Henriques
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